#3 - 🧪 Chem basics - QA to Q mgmt

Quality assurance

Which of the following processes is defined as the method by which a laboratory ensures quality results by closely monitoring the preanalytical, analytical, and postanalytical stages of testing?

Preanalytical stage

Which stage of testing includes everything that precedes test performance, such as test ordering, patient preparation, patient ID, specimen collection, specimen transport, and specimen processing?

Analytical stage

Everything related to the assay itself, including test analysis, quality control, reagents, calibration, and preventive maintenance, is categorized under which stage of testing?

Postanalytical stage

Verification of calculations and reference ranges, review of results, notification of critical values, result reporting, test interpretation by a physician, and follow-up patient care all belong to which stage of testing?

Quality control

Which process is defined as a part of the analytical phase of quality assurance that monitors results from control samples to verify the accuracy of patient results?

The sum of all values divided by the number of values

What is the mathematical definition or formula for the mean as a measure of central tendency?

Median

Which term describes the midpoint of a distribution of data?

Mode

Which measure of central tendency represents the most frequent observation within a data set?

Mean = 7.67, Median = 7, Mode = 7

Given the data set containing the values 1, 1, 2, 3, 5, 6, 7, 7, 7, 8, 11, 13, 14, 14, and 16, what are the calculated values for the mean, median, and mode, respectively?

Range

Which measure of spread or dispersion is defined as the difference between the highest and lowest value and is considered the easiest measure of spread?

Standard deviation

Which value represents the most frequently used measure of variation in laboratory statistics?

Coefficient of variation

Which parameter is defined as an index of precision used to compare the dispersion of two or more groups of data with different units or concentrations?

Directly proportional

Dispersion and SD are

Precision

What is the opposite of dispersion

T-test

Which statistical tool is utilized to determine if there is a significant difference between the means of two groups of data?

F-test

Which statistical test is used to determine if there is a significant difference between the standard deviations of two groups of data?

The mean, median, and mode are identical, and the distribution is symmetric

What unique characteristics are shared by a Gaussian distribution?

Gaussian Distribution

Characterized by symmetrical bell curve. It describes many continuous lab variables and shares several unique characteristics

1.0, or 100%

What is the total area under a normal Gaussian distribution curve?

~95% of the data

According to the 68-95-99 Rule in Bishop 8th edition, what approximate percentage of data falls between plus or minus 2 standard deviations from the mean in a Gaussian distribution?

Accuracy

Which test performance parameter describes the nearness or closeness of assayed values to the true value?

Precision

Which term describes the nearness or closeness of assayed values to each other and is also known as reproducibility?

Reliability

What is defined as the ability of an analytical method to maintain accuracy and precision over an extended period of time?

Practicability

Which performance parameter describes the degree by which a laboratory method can easily be repeated?

Analytical sensitivity

What term defines the ability of an analytical method to measure the smallest concentration of the analyte of interest?

Analytical specificity

What term defines the ability of an analytical method to measure only the analyte of interest?

Reportable range

Which parameter is also known as linearity and is defined as the range of values over which a laboratory can verify the accuracy of a test system?

By testing a minimum of 120 healthy subjects

How is a reference interval established by a laboratory when determining where 95% of healthy subjects fall?

As few as 20 study individuals

How many study individuals are required as a minimum when a laboratory is verifying an existing reference interval through transference?

From 120 to as many as ~700 study individuals

According to the reference interval text box from Bishop 8th edition, a completely new reference interval study is costly and labor-intensive and may require how many study individuals?

As few as 40 study individuals

Transference and validation using method comparison and a smaller sample of healthy individuals represent the most common studies performed in the clinic and often include how many individuals?

Reporting a positive result in a patient who doesn't have the disease

How is a False Positive outcome defined under the diagnostic value characteristics table?

Diagnostic sensitivity

Which term describes the percentage of the population with a disease that tests positive, demonstrating the ability of an analytical method to detect the proportion of individuals with the disease?

TN / (TN + FP) × 100

What is the mathematical formula used to calculate the percentage for diagnostic specificity?

Diagnostic specificity

Which term is defined as the percentage of the population without the disease that test negative, or the ability of an analytical method to detect the proportion of individuals without the disease?

Positive predictive value

Which term describes the percentage of time that a positive test result is correct?
Positive predictive value

Negative predictive value

Which term describes the percentage of time that a negative test result is correct?

[TN / (TN + FP)] x 100

Which formula is used to calculate Diagnostic Specificity (%)?

[TP / (TP + FN)] x 100

Which formula is used to calculate Diagnostic Sensitivity (%)?

[TP / (TP + FP)] x 100

Which formula is used to find the Positive Predictive Value (PPV)?

[TN / (TN + FN)] x 100

Which formula is used to find the Negative Predictive Value (NPV)?

On a regular schedule

How often or on what type of timeline should quality control samples be assayed to verify that a laboratory procedure is performing correctly?

Two different concentrations

How many different concentrations of control materials are generally necessary to maintain an adequate statistical quality control system?

20 days

When a laboratory introduces a new instrument or a completely new lot of reagents, for how many days must the quality control materials be analyzed?

Must resemble human samples

Which of the following is listed as the first characteristic of ideal quality control materials in the provided list?

Shewhart plot

Which alternative name is used to describe the Levey-Jennings control chart?

Deterioration of reagents

What is the main cause when control values are increasing or decreasing for six consecutive runs (Trend)?

Improper calibration

What is the main cause when six consecutive control values are on the same side of the mean (Shift)?

Highly deviating values; control result outside established limits

How are outliers defined under the errors observed on Levey-Jennings charts section?

Warning flag of possible change; Initiates testing of other rules

What is the type of error and required action when 1 control exceeds plus/minus 2s from the mean (1_2s rule)?

Systematic error; Rejection rule

What is the type of error and required action when 10 consecutive controls are on the same side of the mean (10x rule)?

Random error; Rejection rule

What is the type of error and required action when 1 control exceeds plus/minus 3s from the mean (1_3s rule)?

2 consecutive controls differ by > 4s, Random error

What are the specific parameters and error types associated with the R(4s) Westgard rule?

Systematic error; Rejection rule

What is the type of error and required action when 2 consecutive controls exceed 2s from the mean on the same side (2_2s rule)?

Random error; Rejection rule

What is the type of error and required action when 2 consecutive controls differ by more than 4s (R_4s rule)?

Systematic error; Rejection rule

What is the type of error and required action when 4 consecutive controls exceed 1s from the mean on the same side (4_1s rule)?

Present in all measurements; due to chance; no means of predicting it; error that doesn't recur in regular pattern

How is random error defined and differentiated in the text regarding its predictability and recurrence pattern?

1(2s), 1(3s) and R(4s)

Which group of Westgard rules is collectively associated with violations caused by random error?

2(2s), 4(1s) and 10x

Which group of Westgard rules is collectively associated with violations caused by systematic error?

Error due to dirty glassware, use of wrong pipet, voltage fluctuation, sampling error, anticoagulant or drug interference

Which of the following lists contains examples exclusively classified as random errors in the laboratory table?

Dirty photometer, faulty ISE, evaporation or contamination of standards or reagents

Which of the following lists contains examples exclusively classified as systematic errors in the laboratory table?

External quality assessment

By what alternative name is proficiency testing also known as in clinical laboratory science?

Consists of evaluation of method performance by comparison of results versus those of other laboratories for the same set of samples

What is the fundamental definition and method of proficiency testing as described under the basic procedure?

Checking of armband is mandatory

Which action is mandatory regarding patient identification components prior to specimen collection?

Anticoagulants may seriously interfere with some assays

Why should laboratory staff collecting blood samples be thoroughly familiar with handling circumstances and additives?

Test requests that are not clear should be confirmed and clarified before sampling is done and assays are performed

What action must be taken if a test request received in the laboratory is not clear?

Comparison of patient data with previous results; detects specimen mix-up & other errors

How are delta checks defined and what is their primary function in a quality assurance program?

Test results that indicate a potentially life-threatening situation

What is the definition of critical values/ panic values in a clinical laboratory setting?

<40 mg/dL or >500 mg/dL

Which of the following represents the correct critical value limits listed for serum glucose?

All results should be checked at least twice

According to the data reporting section, how many times should all laboratory results be checked?

Schedule of maintenance to keep equipment in peak operating condition; must be documented & must follow manufacturer's specifications & frequencies

What are the requirements for preventive maintenance according to the components of a QA program?

Approach focusing on process improvement as a means to meet a set standard

What is the definition of quality management provided in the final section?

Lean Six Sigma

Which system provides a culture, infrastructure, methodology, and metric for quality improvement, beginning with a belief in the relentless pursuit of continuous improvement?

Project coaches/leaders who dedicate 100% of their time to proactively addressing process and quality problems

What is the role and time commitment of Black Belts within a Lean Six Sigma quality improvement team?

Project team members who contribute 20% of their on-project time while maintaining their normal jobs

What is the specific role and time description assigned to Green Belts in Lean Six Sigma?

Blue Belts

Which color belt represents project sponsors who are mid- to senior-level individuals responsible for reviewing projects, removing organizational barriers, and encouraging team members?

Problem-cause-solution methodology

What methodology does Lean Six Sigma use to improve any process through waste elimination and variation reduction?

Define, Measure, Analyze, Improve, and Control

What does the acronym DMAIC stand for under the Lean Six Sigma sound problem-solving framework?

Trend

Based on the statistical principles of clinical laboratory quality control, a progressive, gradual, and continuous change in data points moving in a single direction over six or more consecutive runs indicates which type of systematic error?

Trend

A medical technology intern tracks the control values for serum calcium over a series of analytical runs. The intern documents that the control results have progressively decreased each day over six consecutive testing cycles due to gradual reagent deterioration. Which quality control anomaly does this directional movement describe?

Shift

While evaluating a daily chemistry instrument log, a laboratory scientist notes that the quality control values for blood urea nitrogen suddenly drop down below the mean line on Tuesday morning due to a sudden change in the reagent lot. The values remain consistently locked on that same low side of the mean for six consecutive runs. This sudden, abrupt baseline change represents which type of error?